fix parsing of chart Y values
fix parsing of chart Y values

Change-Id: I8a33398c3493a88ca388d832b27f4ba3e0c5aa93
Reviewed-on: http://review.couchbase.org/25063
Tested-by: buildbot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Reviewed-by: Pavel Paulau <dd88eded64e90046a680e3a6c0828ceb8fe8a0e7@gmail.com>

couchbase/cbagent,pavel-paulau/cbagent,couchbase/cbmonitor,couchbase/cbmonitor,mikewied/cbagent,vmx/cbagent